函数fft1用经典方法计算信号的功率谱；hanshu.m中用welch方法计算功率谱，并选择不同的窗函数进行了对比；yali.m中用music法对接触压力数据进行功率谱分析-Calculated using the classical method function fft1 power spectrum of the signal hanshu.m using the welch methods calculate the power spectrum, and select a diffe